Jon Leuer was out of the lineup for almost all of last season, playing in just eight games before a mysterious foot injury sidelined him for the short term. When the injury got progressively worse, it ended up shelving the 6-foot-10 forward for the season.

The Pistons training staff tried to figure out the issues, but when the foot was diagnosed as a severe ankle sprain, it curiously didn’t get better. It continued to swell and Leuer did what he needed to help heal.

Things just didn’t get better. Instead of a short-term injury, it ended up keeping him out for 74 games. When Leuer finally got healthy and started working out this summer, he had another freak injury, when his knee buckled — and he had to have another surgery.

“It was definitely a low point to go through the whole rehab process with the ankle and that surgery and feel good and healthy and then play this summer,” Leuer said. “I felt it pop three times and it locked in a 90-degree angle.

“I had surgery on it and knowing I had to go through the whole process again was definitely a low point. Time doesn’t go back; it goes forward — and I’m ready to get healthy and do whatever I can to help this team.”

Leuer is healthy again and has been medically cleared to start practicing. Although he’s not ready to go in full-contact drills, he is doing most of the basketball activities as the Pistons are in training camp this week at Crisler Center in Ann Arbor.

The initial diagnosis of a knee strain was another scare in what has been a harrowing year. He was fearful that the knee injury might be another long-term injury, which might have shelved him for a good part of this year.

After surgery he got the good news that he would be able to work his way back. With new coach Dwane Casey, there’s plenty of optimism that Leuer can be an integral part of the second unit and play different roles to make the reserve group as dynamic as Casey’s was with the Toronto Raptors last season. With his versatility, he can be a power forward or center, which melds well with some of the options that Casey wants to employ with the second unit.

“That is so important. He can also play with Blake (Griffin) at the 5 or whatever it is,” Casey said. “Jon is very versatile in what he can do and play and his experience is off the charts. He’s a Swiss-Army knife that can go in a lot of different direction.”

In his rehab process, Leuer built a stronger relationship with Reggie Jackson, who missed 37 games last season as he rehabbed his ankle injury. The two learned the value of the mental game, as well as the physical toll of rehabilitation.

“I’m excited for him to be getting healthy and be on the right road to recovery. To have somebody to go through that struggle with, I would call it basketball depression,” Jackson said. “It’s not life depression, but being hungry to touch a ball and being able to not do something for so long and it’s something you love and it’s so close and you can’t grasp it.

“Watching his struggle, it allowed me to get outside myself. The more I focused on myself, the more it sucked. The more we got to know each other, it helped with our recovery and we both came out better because of it.”

There were plenty of ups and downs during their time together, with Jackson not wanting to go to some of the early-morning workouts, missing the game that he loved so much. In Jackson’s case, it was the second straight year that an injury sucked away some of his season. He was frustrated — and Leuer became his confidante and sounding board for some of those emotions.

“He’s helpful with having extra energy and motivation on days when I didn’t want to show up. He called me and said, ‘I just thinking about you and wanted to know what doughnut I wanted today,’” Jackson recalled.

“I don’t want to come in and all I want to do is sulk because I can’t play. He brought an extra influence to me in terms of doing the right thing all day every time. Even on days, when I was down on myself, he picked me up. I hope I did the same for him. I’ll always be thankful to Jon for that.”

Jackson and Leuer are the only Pistons who are limited in training camp, but the plan is to have both of them back in time for the first regular-season game.